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Tuesday, April 19, 2011

Virus may be causing Pacific salmon mortalities

Pacific salmon may be dying from a leukemia-type virus, according to a new theory to explain falling wild salmon numbers in the Fraser River. In Canada's Fraser River, a mysterious illness has killed millions of Pacific salmon, and scientists have a new hypothesis about the cause. The wild salmon may be suffering from viral infections similar to those linked to some forms of leukemia and lymphoma, reports McClatchy newspapers.

For 60 years before the early 1990s, an average of nearly eight million wild salmon returned from the Pacific Ocean to the Fraser River each year to spawn. Now the salmon industry is in a state of collapse, with mortality rates ranging from 40 to 95 per cent. The salmon run has been highly variable. The worst year came in 2009, with 1.5 million salmon, followed by the best year in 2010, with 30 million salmon. But the overall trend is downward. Read more ...